Sentry Bots

 After the first Ulthar invasion in the early 70s, inquisitive minds in Pulp City embarked on a project of fighting Ulthar fire with fire! Of course, most of the captured technology got instantly snatched by the military and dragged deep down into their secret labs only to surface years later in this or the other form. But it took Supremes to crack the security codes of the invasion robots brought to Earth by the Uthars.

 The bots were extremely tricky to deal with, any manual attempt to open their thick ceramic hide would set off an auto destruct mechanism.

 When the Heroes of Pulp City realized that somebody was buying all the wrecked bots from around the world, it was already too late. The trace led to Kodo Island, and thus it was almost certain that the Mysterious Man was behind it. Shortly after, the first of the reprogrammed bots fought alongside Nuke in a short and violent battle in a radioactive waste dump in Mexico.

The basic design became very popular, even though the earthly materials used to create bots could never duplicate the defensive potential of the original Ulthar prototypes. The auto destruct mechanism was reprogrammed so that a controlled bot could be turned into a tactical warhead. Mercenary groups, like Trinity Inc. and the warmonging Supremes of Pulp City, found the unfailing loyalty of bots priceless.

Androida of Heavy Metal managed to build on the frame of the Ulthar bot a new technically advanced version that possessed a higher AI and a very efficient and fast tactical computer built in. The protective plates were made of ceramic shields, giving the Advanced Heavy Metal Bots resilience matching the ones of the Supremes. The downside was that the production costs equaled that of a small tank.